A technique of removing interference signals caused by unlicensed personal wireless communication or the like in a wireless communications system is wanted.
As a technique for removing the interference signals, the following technique is known in, for example, Japanese Laid-open Patent Publication No. 2007-6219, as follows.
According to the technique, the interference signals are extracted for each antenna branch, the extracted interference signals are removed, and radio waves from which the interference signals are removed are synthesized.